The invention relates to an indirect ophthalmoscopy contact lens device for observing and treating the fundus of a patient's eye in conjunction with a slit lamp biomicroscope as well as for use in vitreoretinal surgery in conjunction with an operating microscope. Such a device includes a contact lens element and an image forming lens system mounted in a housing, with the image forming lens system being anterior of the contact lens element. The contact lens element has a concave posterior surface with a profile substantially corresponding to the shape of the average cornea for placement on the patient's eye. Light emanating from the patient's retina passes through the contact lens element and is refracted by the image forming lens system to form an aerial image of the patient's fundus anterior of the image forming lens.
An ophthalmoscopic contact lens device of this type is disclosed, for example, in my prior U.S. Pat. No. 5,200,773. The indirect ophthalmoscopy contact lens system described in this patent includes a meniscus contact lens element and a high refractive index biconvex imaging lens combined to provide a very wide field, high resolution image of the fundus, well suited for both fundus observation and pan retinal photocoagulation laser treatment.
U.S. Pat. No. 5,007,729 to Erickson et al, describes a three element ophthalmoscopic contact lens including an entry lens, a contact lens, and a center lens in spaced apart relationship. The center lens is a biconvex lens made of high refractive index optical material. The lens disclosed in this patent provides a wide field of view but suffers from additional surface reflections from its multiplicity of lens surfaces.
While indirect ophthalmoscopy contact lenses made according to the above mentioned patents function satisfactorily, I have continued my efforts to develop even wider-field ophthalmoscopic contact lenses with improved resolution and image clarity, and as well, enhanced depth of field and optical performance, with minimal surface reflections degrading the image and extensive correction of field curvature, astigmatism and distortion.